1. Field of the Invention
The present invention relates to space structure construction systems and in particular to a space structure construction system using flexible star-like joints which can be interlocked with a wide range of tubular elements having different diameters to fabricate three dimensional space structures with straight and curved configurations and which are capable of interlocking inexpensive straws.
2. Description of the Prior Art
Construction systems have fascinated children of all ages for all time. Most construction systems have preset elements which fit together often in a limited variety of arrays. And often today the construction pieces are designed for fabricating a single three dimensional figure.
Various space structure construction systems have been patented. Generally they use a unique connector to which numbers of the same size and shape building elements can be connected to form structures, normally three dimensional in shape. A number of them provide connectors to which hollow tubular building elements may be attached, all of the same internal diameter to fit on the same size protrusions from the central hub of each connector.
U.S. Pat. No. 3,176,428, issued Apr. 6, 1965 to Slingluff, provides flexible resilient straws bendable into loop configurations connected at each end to adjacent rigid spokes around a central rigid hub simulating a propeller as well as other shapes simulating building arch ways and other types of structures. There is no suggestion of inserting the loops into tubes.
U.S. Pat. No. 4,787,191, issued Nov. 29, 1988 to Shima, shows a somewhat flexible flat connector element shaped like a ships wheel on an old sailing ship with short spokes protruding outwardly from a circular rim have an inner opening. Tubular elements are connected at one end to the spokes of one connector and at the other end to the spokes of another connector in multiplicity to create three dimensional space frame structures. Elements can interconnect through the inner opening of the connector.
U.S. Pat. No. 3,648,404, issued Mar. 14, 1972 to Ogsbury, claims a three dimensional connector unit having radial arms extending in X, Y and Z directions with slotted ends to receive tubular members press fit onto the arms to form three dimensional space frame structures.
U.S. Pat. No. 5,049,105, issued Sep. 17, 1991 to Glickman, describes an injection molded flat hub connector having a radial spokes configuration with slotted spokes to receive tubular elements, such as straws, press fit onto the spokes to form three dimensional space frame structures. A central circular rim in the hub can also receive tubular elements connected thereto expanding the structure into the third dimension.
U.S. Pat. No. 4,078,328, issued Mar. 14, 1978 to Rayment, discloses a flat connector unit having a central circular opening therethrough and radiating arms having bulbous outer ends to receive deformable plastic tubes connected to the bulbous ends so that the tubes may be rotated around the arms. Tubular elements may be inserted through the central opening to expand the structure to three dimensions.
U.S. Pat. No. 5,318,470, issued Jun. 7, 1994 to Denny, indicates a modular building assembly having a donut shaped hub with rounded protuberances extending therefrom around the outer circular edge to receive tubular members attached thereto. It also includes hemispheres with rounded protuberances attachable to each side of the hub to create a hemispheric hub with rounded protuberances extending outwardly in all directions to create three dimensional space frame structures when interconnected with other hubs using the tubular members.
U.S. Pat. No. 3,830,011, issued Aug. 20, 1974 to Ochrymowich, puts forth deformable extruded tubular rods connected to deformable sheet material connectors stamped out of thermoplastic in various configurations with a varied number of arms extending from a central hub. The flexibility of the rods and the connectors enables three dimensional space frame structures.
There is a need for a connector which can receive a wide variety of sizes of tubular building elements to create more variety in the construction and permit the use of diverse elements, such as straws which are inexpensive to buy in quantity and can be found in a wide variety of diameters, lengths, and colors.
An object of the present invention is to provide a space structure construction connector which has a spoke-like array of flexible arms that can receive a wide variety of sizes of tubular building elements attached to the arms for creating structures.
Another object of the present invention is to provide a central opening in the connector for receiving a two-armed connector element or a tubular building element therein for extending the structure in three dimensions.
One more object of the present invention is to provide a spoke-like array flexible arms for receiving straws which can be purchased inexpensively in bulk to extend the use of the space structure construction kit considerably.
An additional object of the present invention is to provide a connector having a spoke-like array of flexible arms, each capable of bending in any direction to allow curved or other unusually shaped constructions.
In brief, a connector has a central circular hub with an opening therethrough and a series of flexible arms radiating out from the hub in a spoke-like array. The connectors may have any number of spaced radiating arms, including 2-10 arms, as well as two in the connector inserted through the central hub opening.
Each arm may be a loop of flexible material for receiving an end of a tubular building element pressed over the arm compressing the loop, which then exerts an outwardly directed friction force on the inner walls of the tubular element to retain the element in place. Other possible arm configurations include a rod having an end cap and a movable washer element capable of moving along the rod to compress a flexible material between the cap and the washer, causing the flexible material to expand to exert a retaining force on a tubular building element inserted over the arm. Variations for the flexible material encircling the rod include a nylon coil spring, expansible accordion plastic or rubber, a nylon loop with ribbed grips, expansion plastic rubber or foam, a series of strips of nylon cable, a series of flexible arms radiating out from the rod, or other flexible material. The arm may also be a spring-loaded split arm (nylon) having an encircling rubber grip material.
The base of each arm adjacent to where it connects to the central hub may have a portion of nylon or other flexible material twisted by heat forming to a ninety or one-hundred-eighty degree twist to make the arm more flexible and allow each arm to bend in any direction for forming interesting structural shapes.
The two-armed connector part that is inserted through the central circular hub opening may be provided with a clipping mechanism, such as flexing plastic arms with a protruding retaining portion, so the two-armed connector part may be inserted into the central hub opening and locked in place by the protruding retaining portion which bends inwardly as the two-armed connector passes through the central hub and then clicks outwardly to lock the two-armed connector part in place in the central hub opening, thereby creating a combined connector with arms extending in a variety of directions for building three dimensional constructions.
An advantage of the present invention is that it has the flexibility of arm movement to create a wide variety of three dimensional structures.
Another advantage of the present invention is that it has flexible retaining portions on each arm so that each arm has the ability to receive and retain a wide variety of sizes and shapes of open-ended building elements attached thereto.